Subduction zones lawsonite

In basalts, lawsonite is the only hydrous phase which is stable in the deep mantle and this phase dehydrates at the depth of the mantle transition zone. Similarly in subducted pelagic sediments there is a series of hydrated aluminum silicates and oxides (including the phase Egg - AlSiOs.OH) which also remain stable down to transition zone depths (Williams Hemley, 2001). 

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